Correcting for subcutaneous fat: Does it improve the correlation between vastus lateralis echo intensity and physical performance in older women?

Abstract

Numerous studies have corrected the echo intensity of the vastus lateralis for subcutaneous fat thickness. However, it is unclear if correction for subcutaneous fat improves the correlation between vastus lateralis echo intensity and physical performance. We aimed to examine the correlations between vastus lateralis muscle morphology parameters and physical performance outcomes in older women. Twenty healthy older women (67 ± 4 years) participated in this study. Muscle cross‐sectional area, raw and corrected echo intensity and subcutaneous fat thickness were determined from ultrasound scans of the vastus lateralis. Physical performance was assessed from timed up‐and‐go and 6 min walk tests. Raw echo intensity was significantly related to timed up‐and‐go scores (r = 0.552, p = 0.012) and 6 min walk distance (r = −0.462, p = 0.040), whereas corrected echo intensity was not significantly associated with these performances (r = 0.433, p = 0.056 and r = −0.373, p = 0.105). There was a nonsignificant correlation between raw echo intensity and subcutaneous fat thickness (r = 0.353, p = 0.126). There were also nonsignificant correlations between muscle cross‐sectional area and timed up‐and‐go scores (r = −0.189, p = 0.426) and 6 min walk distance (r = 0.298, p = 0.201). The results of our study showed that raw echo intensity correlated better than corrected echo intensity with physical performance. These findings question the need to correct the echo intensity of the vastus lateralis for subcutaneous fat thickness in older adults.

Exploring the associations between skeletal muscle echogenicity and physical function in aging adults: A systematic review with meta-analyses

“…The 51 included studies included 5095 (∼2759 females, ∼2301 males) participants, aged 72.5±5.8 years of age. 7,11,12,14–24,26–62 Twenty-seven studies included males and females, 14,17,20,23,24,26,28–30,32,33,36–38,40,42,45–47,49,54,57–62 while 16 included only males, 7,11,15,16,18,19,21,22,31,34,39,41,48,50,52,56 seven included only females, 27,35,43,44,51,53,55 a single study did not report sex, 12 while another did not delineate sex when reporting age or participant numbers; 61 explaining the approximate values in the previous sentence. Two studies included participants with ‘metabolic syndrome’ or diabetes, 20,33 and single studies included participants with chronic obstructive pulmonary disease, 42 USA Veterans, 11 ‘frail’, 24 outpatients, 63 nursing home residents, 23 or regularly participated in competitive tennis.…”

“…31 Non-corrected echogenicity was used in 49 studies, 7,11,12,14–20,22–24,26–49,51–62 while subcutaneous fat-correction was reported or obtained in 12 studies. 15,16,18,19,21,30,40,48,50,51,54,59 Both non-corrected and corrected values and/or correlations were found or obtained from 10 studies. 15,16,18,19,30,40,48,51,54,59…”

“…15,16,18,19,21,30,40,48,50,51,54,59 Both non-corrected and corrected values and/or correlations were found or obtained from 10 studies. 15,16,18,19,30,40,48,51,54,59…”

“…The rectus femoris was the most common (n=33) isolated muscle included in correlations, 7,11,12,14,17,18,20,22–24,28,29,31–37,39–41,43,46,47,53–57,59–62 followed by the vastus lateralis (n=11), 12,28,29,36,38,39,51,53,56,59,62 medial gastrocnemius (n=7), 15,16,32,33,36,40,48 vastus intermedius (n=7), 12,20,41,47,53,56,57 lateral gastrocnemius (n=4), 15,22,40,48 biceps brachii (n=4), 22,23,32,33 vastus medialis (n=3), 12,53,56 tibialis anterior (n=3), 22,36,42 and triceps brachii (n=3). 22,32,33 Single studies reported correlations with the multifidus, 44 erector spinae, 44 gluteus medius, 38 masseter, 58 psoas major, 44 or rectus abdominis 22 muscles.…”

“…The most common functional test was peak force or torque during isometric knee extension (n=22) 7,12,14,17,18,20,22,23,27,31,35,39,43,47,48,53–57,59,60 or flexion (n=2), 22,52 followed by measures of grip strength (n=20), 11,14,20,22–24,28,32,33,37,40,45,46,48,53,57,58,60–62 walking speed (n=16), 14,17,20,32,33,36,40,44,45,47,53,54,57,58,60,61 sit-to-stand (n=16), 22,23,28,29,38,40,41,43,49,53,56,57,59–62 timed up-and-go (n=10), 17,20,38,45,47,49,51,57,60,61 concentric knee extension force or power, (n=8) 11,22,30,31,39,45,48,56 isometric or concentric plantar-flexion (n=5) strength, power or velocity, 15,16,19,26,48 single leg balance or posture (n=5), …”